remove unused `_do_idle_check` function paramter

[jangjichang]

Describe the solution you'd like [DELETE THIS LINE] A clear and concise description of what you want to happen. [DELETE THIS LINE] 어떤 기능이 있으면 좋겠는지 자세히 설명해주세요. Can i remove paramter of _do_idle_check function?

fuction get context, source, event parameter. but not use these parameter in function

Describe alternatives you've considered [DELETE THIS LINE] A clear and concise description of any alternative solutions or features you've considered. [DELETE THIS LINE] 혹시 다른 대안들을 생각해본 적이 있다면 함께 적어주세요.

i delete three parameter, but fail mypy lint

mypy error message:

16:31:17.74 [ERROR] Completed: Typecheck using MyPy - mypy failed (exit code 1).
src/ai/backend/manager/idle.py:127: error: Argument 3 to "consume" of "EventDispatcher" has incompatible type "Callable[[], Coroutine[Any, Any, None]]"; expected "Union[Callable[[None, AgentId, DoIdleCheckEvent], Coroutine[Any, Any, None]], Callable[[None, AgentId, DoIdleCheckEvent], None]]"
Found 1 error in 1 file (checked 515 source files)

Additional context [DELETE THIS LINE] Add any other context or screenshots about the feature request here. [DELETE THIS LINE] 기능 요청에 대해 보다 잘 이해할 수 있는 다른 맥락을 기술해주세요.